Generic LDPC Encoder with Speculative Recursion for Parity Generation
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Solution Overview
Problem
Low-density parity check (LDPC) codes face challenges in implementing low error floors without increasing code block length, which can require significant memory and computational resources, limiting their flexibility.
Innovation Solution
The development of LDPC encoders with parameter programmability, incorporating an input buffer, matrix-vector multiplication unit, and inversion unit capable of using various inversion mechanisms such as recursive computation, speculative recursion, and blockwise inversion to efficiently generate parity symbols for LDPC codes with different parity check matrix structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC codes use large code block length to achieve low error floors, then error floor performance is improved, but memory and computational requirements increase
Solution Approach 1:
The parity check matrix is divided into sub-matrices, and the encoding process is segmented into multiple steps involving sub-encoding and parity generation. This allows the encoding of long codes to be broken down into manageable operations that can be performed with reduced memory requirements at each step.
Solution Approach 2:
The encoder pre-calculates and stores certain parity values and syndrome information during the encoding process. This preliminary action allows the decoder to operate more efficiently with reduced computational requirements during actual decoding, as much of the heavy lifting has already been done during encoding.
2Reliability
If LDPC encoders are designed with high computational power to handle lengthy codes, then error floor performance is improved, but flexibility decreases
Solution Approach 1:
The encoder is designed with a universal structure that can handle multiple LDPC code configurations through programmable parameters. The same hardware architecture can be configured to encode different code lengths and rates by loading appropriate parity check matrices and adjusting control parameters, making it adaptable to various applications without sacrificing performance.
Solution Approach 2:
The encoder incorporates dynamic parameter adjustment capabilities, allowing it to adapt its operation based on the specific code configuration being used. Control logic dynamically adjusts encoding parameters such as sub-matrix dimensions, iteration counts, and resource allocation based on the desired code rate and length, maintaining flexibility across different operating conditions.
3Reliability
If LDPC encoders use large memory buffers to support lengthy codes, then low error floors are achieved, but device complexity increases
Solution Approach 1:
Memory requirements are segmented and distributed across multiple smaller memory units rather than requiring one large buffer. The encoder processes data in blocks and uses smaller memory units to store intermediate results, parity information, and syndrome values for each block, reducing the peak memory requirement while maintaining the ability to handle long codes.
Solution Approach 2:
The encoder employs techniques to discard intermediate computation results that are no longer needed and recover or regenerate them when required. This allows the system to operate with smaller memory buffers by temporarily storing only essential information and recomputing or retrieving other values as needed during the encoding process.
Data Source
AI summary
Systems and methods are provided for encoding data based on an LDPC code using various inversion mechanisms to obtain parity bits. In some embodiments, an LDPC encoder may compute parity bits using a speculative recursion and correction mechanism. In these embodiments, the LDPC encoder may initiate a recursion using at least one speculative value in place of the actual value for a parity component. The speculative values may then be corrected using a correction factor. In other embodiments, an LDPC encoder is provided that can perform a blockwise inversion mechanism. This mechanism may be used on LDPC codes with parity check matrices having a parity portion composed partially of a large triangular matrix. In still other embodiments, a generic LDPC encoder is provided. The generic LDPC encoder can implement a variety of different encoding techniques, such as different inversion mechanisms, and may be processor-based or finite state machine-based.